1. Field of the Invention
The present invention is directed to a multilayer film. The present invention is also directed to a backlight unit and a liquid crystal display into which the multilayer film is incorporated.
2. Background
Liquid crystal display, also known as LCD, is an electronic device that transforms electrical signals into visual signals by utilizing change of transmittance of liquid crystals according to applied voltages.
As is well known in the art, liquid crystal display is a non-emitting display device. Thus, liquid crystal display needs to use an external light source unit for illuminating a viewing plane of a liquid crystal panel from outside in order to display visual information. Hereinafter, a conventional liquid crystal display is described in detail with reference to the figures.
FIG. 1 is a perspective view illustrating a liquid crystal display.
Referring to FIG. 1, the liquid crystal display 10 comprises a liquid crystal panel 20 and a backlight unit 30 disposed at backside of the liquid crystal panel. The liquid crystal panel 20 receives a light provided by the backlight unit 30 to display images.
In general, the liquid crystal panel 20 comprises a pair of transparent substrates, a liquid crystal layer inserted between transparent substrates, a color filter, black matrix, a pixel electrode, a common electrode, and a TFT array.
The backlight unit 30 comprises a light source unit 31, a light guide plate 32, a reflector 33, and optical sheets 34, 35 and 36.
The conventional liquid crystal display 10 comprises optical sheets 34, 35 and 36. The optical sheets 34, 35 and 36 may comprise a diffuser sheet 34, a prism sheet 35, and a reflective polarizer film 36.
However, the conventional liquid crystal display has a disadvantage to use a plurality of optical sheets, thereby increasing the manufacturing cost. Another disadvantage is that the display's quality is decreased by thermal deformation of the optical sheet when a heat generated from the light source is transmitted to the optical sheet. Also, the prism sheet may be deformed easily by outer shock, and so should be handled carefully.